The following discussion of the background of the invention is merely provided to aid the reader in understanding the invention and is not admitted to describe or constitute prior art to the present invention.
Skin cancer is the most common of all cancers, afflicting more than a million Americans each year, a number that is rising rapidly. It is also the easiest to cure, if diagnosed and treated early. If allowed to progress to the point where it spreads to other sites (metastasizes), the prognosis (forecast) is very poor. More than 8,000 melanoma deaths now occur per year.
Melanoma most often appears as an asymmetrical, irregularly bordered, multicolored or tan/brown spot or growth that continues to increase in size over time. It may begin as a flat spot and become more elevated. In rare instances, it may not be pigmented.
Dysplastic nevi (atypical moles) are unusual or benign moles that may resemble melanoma. People who have them are at increased risk of developing single or multiple melanomas. The higher the number of these moles someone has, the higher the risk; those who have 10 or more have 12 times the risk of developing melanoma compared to the general population. Dysplastic nevi are found significantly more often in melanoma patients than in the general population.
Melanoma is distinguished from nevi, other forms of cancer, and normal skin on the basis of clinical presentation and histopathological examination of a skin biopsy, usually a formalin fixed, paraffin embedded (FFPE) sample. Considerable expertise is required to reliably distinguish between nevi and melanoma.
This application describes novel microRNA biomarkers with microRNA array and RT-PCR to better characterize dysplastic nevi, malignant melanoma and metastatic melanoma. miRNA can therefore serve as an adjunct to histopathology for correct classification of melanoma, nevi and other conditions, especially where there is doubt as to the diagnosis.